How to load a PHP class into a PHP functions

[blmg2009]

Hi, 

 

I'm struggling to understand how to load a PHP classes for my database into a php function. 

 

My class in on another file, which is included into my page. 

 

I then have a function that usings the class of $database->query in the function, but for some reason this doesn't work. 

 

However the class works on the page outside of the function, is there someway I must load the class into my function?

 

Thanks for reading. 

[blmg2009]

 

include_once"database.php";
 
function test($one, $two, $three)
{
   $database->query(...); /// doesn't work inside this function
}
 
$database->query(...); /// works outside the function

[mac_gyver]

the answer is similar to one of your previous threads, you pass the instance of the database into your function as a call time parameter.

[blmg2009]

Thank you for taking the time to reply, I have tried this too

 

but I get the following error: Argument 4 passed to test() must be an instance of Database, none given

 

Sorry I'm new to PHP. 

[blmg2009]

 

include_once"database.php";
 
function test($one, $two, $three, Database $database)
{
   $database->query(...); /// doesn't work inside this function
}
 
$database->query(...); /// works outside the function

[ginerjm]

WHAT is that word 'Database' doing in that header?

 

You need to pass the variable that represents your current instance of database class.  So

 

test(!one,$two,$three,$database)

 

is what you want.

 

IMHO - if you are such a newcomer to PHP, why are you getting into classes and whatever else (objects?) when you don't even know how to pass arguments to a function or how to format the header of one?  That is a basic premise of functions in any language that supports functions and you don't understand it.

[requinix]

WHAT is that word 'Database' doing in that header?

Type hinting.

 

blmg2009, keep it there. It's a good thing.

[ginerjm]

Type hinting in PHP?  I have not seen that mentioned before.  My bad.

[KevinM1]

Type hinting in PHP?  I have not seen that mentioned before.  My bad.

 

Type hinting has been in PHP for, well, years.

[ginerjm]

I just have not run across it.  That's all.

[trq]

I just have not run across it.  That's all.

Then you're doing it wrong.

[ginerjm]

doing what wrong? 

[trq]

doing what wrong?

 

PHP

[.josh]

include_once"database.php";
 
function test($one, $two, $three, Database $database)
{
   $database->query(...); /// doesn't work inside this function
}
 
$database->query(...); /// works outside the function

 

 

So, some debugging 101 here.. you got an error that was essentially the result the variable not being within the scope of the function. So you updated your function declaration and now you are getting another error, which basically means you aren't passing to test what it expects.  To me, this sounds like you likely essentially have the same issue before, except backing up the chain a notch.  

 

So, where/how are you calling test()?  Did you update where you are calling it to have it actually pass a Database type object when you call it?  If so, are you calling test() within some other function, and $database isn't exposed to it, in the same way it wasn't exposed here?

 

Follow the trail, make sure $database is actually exposed, same as you already did here. 

[blacknight]

if $database is defined in the db file you could just call it as a global in the function like 

function test($one, $two, $three)
{
   global $database;
   $database->query(...); /// doesn't work inside this function
}

some people dont like to do this but it does work

[mac_gyver]

@blacknight, it's not that people don't like it, it's that it produces bad code that's harder to maintain because it requires that the programmer keep track of a greater amount of information, making his job harder and making it harder for anyone in the future to make use of the code or make changes to the code.

 

using global to being a value into a function breaks the black-box model of writing functions. the only interaction a function should have with the calling code is at the point where the function gets called.